Bacta Pump reads:

At the start of your activation, recover one strain or discard one harmful condition.

How does this work in relation to other "at the start of your activation" abilities? This question came up last night during our campaign when Ko-Tun was activating with Arms Distribution. My understanding is that if Ko-Tun is at 4/4 strain, she can recover one strain at the start of her activation and then use Arms Distribution during the "at the start of your activation" timing window. The part that we were less sure about is that if Ko-Tun is at 0/4 strain, can she use Arms Distribution first and then use Bacta Pump to recover the strain gained from Arms Distribution?

How does the timing window for "at the start of your activation" work? When does the "start of your activation" end and can players decide what order to resolve abilities with that same timing window?

Bacta Pump is Ko-Tun's ability, so she can decide the order of "at the start of your activation" abilities.

(Start of an activation is a single trigger, it is not a phase. Just like end of an activation is a single trigger, not a phase. As long as you perform abilities with "start of your activation" trigger, you are at that trigger. If you perform a during your activation ability, or an action, you are during the activation and not at the start of an activation.

See also: Quick Draw.)