Didn’t notice she peed

My daughter (who’s a week shy of 2 years old) is on day 5 of potty training. Using the method outlined in the oh crap potty training book. It’s day 3 of pants and she’s only had 1 accident per day. Tonight, my husband took her outside because she was going stir crazy inside. At some point she peed and he didn’t notice. He only noticed later (her shorts were a light colour and the ground was wet outside). She didn’t have any reaction to peeing (never said oh no or showed discomfort at being wet). I’m worried that 1) because he didn’t catch her peeing and was unable to reiterate to her that pee goes in the potty; and 2) she doesn’t seem to realize she peed. I’m worried that this incident derailed what I thought was going so well. Please tell me it didn’t! And also, should I be worried that we’re on day 5 and she didn’t seem to react to having peed in her pants?