It says in the rules under “Rounds of Combat” > “Step 2: Enemies Move & Non-Harm Actions” that actions that don’t directly deal harm are resolved at that step. So the Writher would place a spike pod during Step 2 i.e.
Before the quickstarter launched, there was a playtest of the rules. Those rules have since been updated, and that version is no longer available. In those rules, under "Rounds of combat", Step 2 was just "Enemies Move," which is why I left the feedback I did. That file was named "RUNE Complete Rules.pdf," and I just checked it to make sure I wasn't going crazy.