A player may choose not to trigger an optional deploy ability that would end their turn early, if the ability gives them the option not to use it.

This is supported by the following rule:

• "If possible, trigger the deploy ability ( ) of the card played, unless it gives you the option not to (e.g., 'You may gain...')."
  (page 3)

If the deploy ability is worded as optional (using "You may..."), the player can choose not to use it, and therefore avoid ending their turn early. If the ability is not optional, the player must resolve it if possible, even if it ends their turn early.

Source: page 3

Source: Core Rulebook (pp. 1, 3, 4, 6)