diff --git a/llama/runner/runner.go b/llama/runner/runner.go
index c3d0353f..db8092f3 100644
--- a/llama/runner/runner.go
+++ b/llama/runner/runner.go
@@ -300,6 +300,7 @@ func (s *Server) removeSequence(seqIndex int, reason string) {
 	close(seq.embedding)
 	seq.cache.InUse = false
 	s.seqs[seqIndex] = nil
+	s.seqsSem.Release(1)
 }
 
 func (s *Server) run(ctx context.Context) {
@@ -649,7 +650,7 @@ func (s *Server) completion(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Ensure that a place to put the sequence is available
+	// Ensure there is a place to put the sequence, released when removed from s.seqs
 	if err := s.seqsSem.Acquire(r.Context(), 1); err != nil {
 		if errors.Is(err, context.Canceled) {
 			slog.Info("aborting completion request due to client closing the connection")
@@ -658,9 +659,9 @@ func (s *Server) completion(w http.ResponseWriter, r *http.Request) {
 		}
 		return
 	}
-	defer s.seqsSem.Release(1)
 
 	s.mu.Lock()
+	found := false
 	for i, sq := range s.seqs {
 		if sq == nil {
 			seq.cache, seq.inputs, err = s.cache.LoadCacheSlot(seq.inputs, req.CachePrompt)
@@ -674,11 +675,17 @@ func (s *Server) completion(w http.ResponseWriter, r *http.Request) {
 
 			s.seqs[i] = seq
 			s.cond.Signal()
+			found = true
 			break
 		}
 	}
 	s.mu.Unlock()
 
+	if !found {
+		http.Error(w, "could not find an available sequence", http.StatusInternalServerError)
+		return
+	}
+
 	for {
 		select {
 		case <-r.Context().Done():
@@ -742,7 +749,7 @@ func (s *Server) embeddings(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Ensure that a place to put the sequence is available
+	// Ensure there is a place to put the sequence, released when removed from s.seqs
 	if err := s.seqsSem.Acquire(r.Context(), 1); err != nil {
 		if errors.Is(err, context.Canceled) {
 			slog.Info("aborting embeddings request due to client closing the connection")
@@ -751,9 +758,9 @@ func (s *Server) embeddings(w http.ResponseWriter, r *http.Request) {
 		}
 		return
 	}
-	defer s.seqsSem.Release(1)
 
 	s.mu.Lock()
+	found := false
 	for i, sq := range s.seqs {
 		if sq == nil {
 			seq.cache, seq.inputs, err = s.cache.LoadCacheSlot(seq.inputs, req.CachePrompt)
@@ -764,11 +771,17 @@ func (s *Server) embeddings(w http.ResponseWriter, r *http.Request) {
 			}
 			s.seqs[i] = seq
 			s.cond.Signal()
+			found = true
 			break
 		}
 	}
 	s.mu.Unlock()
 
+	if !found {
+		http.Error(w, "could not find an available sequence", http.StatusInternalServerError)
+		return
+	}
+
 	embedding := <-seq.embedding
 
 	if err := json.NewEncoder(w).Encode(&EmbeddingResponse{