in highschool track all the varsity 400m guys ran between 52-58 seconds. on some practice days all sprinters were forced to run 400m multiple times; those who didn't overexert and die in the last 150m usually finished with a time of 60-74 seconds. new guys who were still fit but didn't run much and/or weren't used to sprinting more than 200m were at the higher end of that range
that said im just going to assume op isn't in shape, was wearing street clothes, and didn't warm up or stretch beforehand. so 300m in under a minute is kind of hard to believe