diff --git a/pymc/database/ram.py b/pymc/database/ram.py
index <HASH>..<HASH> 100644
--- a/pymc/database/ram.py
+++ b/pymc/database/ram.py
@@ -129,7 +129,7 @@ class Trace(base.Trace):
     def __getitem__(self, index):
         chain = self._chain
         if chain is None:
-            return concatenate(self._trace.values())[index]
+            return concatenate(list(self._trace.values()))[index]
         else:
             if chain < 0:
                 chain = range(self.db.chains)[chain]
Dodge segfault from np.concatenate: it can't handle dict_values.