Boston has not played well for a while now. They are 4-6-0 in their last 10 and 3-4-0 in their last 7 OTR (with 2 wins in SO). In those last 7 OTR they have given up 4 or more goals 4/7 times.
Thomas is expected to start tonight. He took the loss in MINN on Sunday. In Feb he is an ordinary 3-3-0 with GAA of 2.51 and SV% of 0.907 in 7 appearances.

St.Louis has one of the best home records in the league and have been scoring well at home recently. In their last 7 at home they are 6-0-1 and have scored 3 or more goals 4/7 times while allowing 2 or less 6/7 times (with 3 shutouts).
Elliot gets the start for St.Louis. In Feb he has a record of 5-1-0 with GAA of 1.06 and SV% of 0.953. At home this season he has a record of 12-1-2 with GAA of 1.32 and SV% of 0.946.

So, St.Louis has been consistent and even improving recently while Boston has been shaky.

Prediction: 4-1 for St.Louis