diff --git a/dorado/cli/aligner.cpp b/dorado/cli/aligner.cpp
index ee6739e45..9bda41ff7 100644
--- a/dorado/cli/aligner.cpp
+++ b/dorado/cli/aligner.cpp
@@ -107,11 +107,10 @@ int aligner(int argc, char* argv[]) {
     add_pg_hdr(header);
 
     PipelineDescriptor pipeline_desc;
-    auto aligner = pipeline_desc.add_node<Aligner>({}, index, kmer_size, window_size,
-                                                   index_batch_size, aligner_threads);
     auto hts_writer = pipeline_desc.add_node<HtsWriter>({}, "-", HtsWriter::OutputMode::BAM,
                                                         writer_threads, 0);
-    pipeline_desc.add_node_sink(aligner, hts_writer);
+    auto aligner = pipeline_desc.add_node<Aligner>({hts_writer}, index, kmer_size, window_size,
+                                                   index_batch_size, aligner_threads);
 
     // Create the Pipeline from our description.
     std::vector<dorado::stats::StatsReporter> stats_reporters;
@@ -146,7 +145,8 @@ int aligner(int argc, char* argv[]) {
     tracker.summarize();
 
     spdlog::info("> finished alignment");
-
+    spdlog::info("> total/primary/unmapped {}/{}/{}", hts_writer_ref.get_total(),
+                 hts_writer_ref.get_primary(), hts_writer_ref.get_unmapped());
     return 0;
 }
 
diff --git a/dorado/cli/basecaller.cpp b/dorado/cli/basecaller.cpp
index 92f7f88d4..74eb1f7ad 100644
--- a/dorado/cli/basecaller.cpp
+++ b/dorado/cli/basecaller.cpp
@@ -148,11 +148,10 @@ void setup(std::vector<std::string> args,
             {read_converter}, min_qscore, default_parameters.min_sequence_length,
             std::unordered_set<std::string>{}, thread_allocations.read_filter_threads);
 
-    auto mod_base_caller_node = PipelineDescriptor::InvalidNodeHandle;
     auto basecaller_node_sink = read_filter_node;
 
     if (!remora_runners.empty()) {
-        mod_base_caller_node = pipeline_desc.add_node<ModBaseCallerNode>(
+        auto mod_base_caller_node = pipeline_desc.add_node<ModBaseCallerNode>(
                 {read_filter_node}, std::move(remora_runners),
                 thread_allocations.remora_threads * num_devices, model_stride, remora_batch_size);
         basecaller_node_sink = mod_base_caller_node;
diff --git a/dorado/read_pipeline/HtsWriter.cpp b/dorado/read_pipeline/HtsWriter.cpp
index 56f1a8b2f..24d8eb592 100644
--- a/dorado/read_pipeline/HtsWriter.cpp
+++ b/dorado/read_pipeline/HtsWriter.cpp
@@ -58,7 +58,6 @@ HtsWriter::~HtsWriter() {
     terminate_impl();
     sam_hdr_destroy(m_header);
     hts_close(m_file);
-    spdlog::info("> total/primary/unmapped {}/{}/{}", m_total, m_primary, m_unmapped);
 }
 
 HtsWriter::OutputMode HtsWriter::get_output_mode(const std::string& mode) {
diff --git a/dorado/read_pipeline/HtsWriter.h b/dorado/read_pipeline/HtsWriter.h
index f0764ee4a..47c4cad27 100644
--- a/dorado/read_pipeline/HtsWriter.h
+++ b/dorado/read_pipeline/HtsWriter.h
@@ -28,6 +28,9 @@ class HtsWriter : public MessageSink {
 
     int set_and_write_header(const sam_hdr_t* header);
     static OutputMode get_output_mode(const std::string& mode);
+    size_t get_total() const { return m_total; }
+    size_t get_primary() const { return m_primary; }
+    size_t get_unmapped() const { return m_unmapped; }
 
 private:
     void terminate_impl();
diff --git a/dorado/read_pipeline/ReadPipeline.cpp b/dorado/read_pipeline/ReadPipeline.cpp
index 199947a68..d736cd388 100644
--- a/dorado/read_pipeline/ReadPipeline.cpp
+++ b/dorado/read_pipeline/ReadPipeline.cpp
@@ -374,7 +374,8 @@ void MessageSink::send_message_to_sink(int sink_index, Message &&message) {
 
 void Pipeline::push_message(Message &&message) {
     assert(!m_nodes.empty());
-    dynamic_cast<MessageSink &>(*m_nodes.back()).push_message(std::move(message));
+    const auto source_node_index = m_source_to_sink_order.front();
+    dynamic_cast<MessageSink &>(*m_nodes.at(source_node_index)).push_message(std::move(message));
 }
 
 stats::NamedStats Pipeline::terminate() {
diff --git a/tests/PipelineTest.cpp b/tests/PipelineTest.cpp
index d9d69d21a..83833b12f 100644
--- a/tests/PipelineTest.cpp
+++ b/tests/PipelineTest.cpp
@@ -1,3 +1,4 @@
+#include "MessageSinkUtils.h"
 #include "read_pipeline/NullNode.h"
 #include "read_pipeline/ReadPipeline.h"
 
@@ -89,7 +90,7 @@ TEST_CASE("Creation", TEST_GROUP) {
 }
 
 // Tests destruction order of a random linear pipeline.
-TEST_CASE("LinearDestructionOrder") {
+TEST_CASE("LinearDestructionOrder", TEST_GROUP) {
     // Node that records destruction order.
     class OrderTestNode : public MessageSink {
     public:
@@ -136,3 +137,35 @@ TEST_CASE("LinearDestructionOrder") {
     // Verify that nodes were destroyed in source-to-sink order.
     CHECK(std::equal(destruction_order.cbegin(), destruction_order.cend(), indices.cbegin()));
 }
+
+// Test inputs flow in the expected way from the source node.
+TEST_CASE("PipelineFlow", TEST_GROUP) {
+    // NullNode passes nothing on, so the sink should get no messages
+    // if they are sent to that node first.
+    {
+        // Natural construction order: sink to source.
+        PipelineDescriptor pipeline_desc;
+        std::vector<dorado::Message> messages;
+        auto sink = pipeline_desc.add_node<MessageSinkToVector>({}, 100, messages);
+        pipeline_desc.add_node<NullNode>({sink});
+        auto pipeline = dorado::Pipeline::create(std::move(pipeline_desc));
+        REQUIRE(pipeline != nullptr);
+        pipeline->push_message(std::shared_ptr<dorado::Read>());
+        pipeline.reset();
+        CHECK(messages.size() == 0);
+    }
+
+    {
+        // Peverse construction order: source to sink.
+        PipelineDescriptor pipeline_desc;
+        std::vector<dorado::Message> messages;
+        auto null_node = pipeline_desc.add_node<NullNode>({});
+        auto sink = pipeline_desc.add_node<MessageSinkToVector>({}, 100, messages);
+        pipeline_desc.add_node_sink(null_node, sink);
+        auto pipeline = dorado::Pipeline::create(std::move(pipeline_desc));
+        REQUIRE(pipeline != nullptr);
+        pipeline->push_message(std::shared_ptr<dorado::Read>());
+        pipeline.reset();
+        CHECK(messages.size() == 0);
+    }
+}
\ No newline at end of file