Nixon looks only at 1500m. His personal splits today were 55.0 (Vickson Polonet, second pacer, was behind the first rabbit in 54.7 and Nixon was immediately behind him), 1:51.2, and remained alone after 1100m.
In Kenyan Trials there are no heats. The event is on 23rd June, and only 15 athletes selected between who has the best limit, and the top runners in National Championships (that are on 14/15/16 of June), can compete.
AK selects runners for African Championships (26.06 / 1.07 in Benin) from National Championships, since the athletes in Olympic Trials cant be ready for going Benin with the competitions starting 3 days later.