Why do my bots in pygame move at such an inconsistent speed?

So my problem is that my bot will move at an inconsistant speed and sometimes not even move. I've tried changing fps with clock.ticks(30) (And less then that) but it just won't go any smoother!

pygame.init()
clock = pygame.time.Clock()

bot4x = random.randint(0, 600)
bot4y = random.randint(0, 600)

randb4 = round(random.randint(0, 4))

def bot4():
    screen.blit(pygame.image.load("DOT.png"), (bot4x, bot4y))

clock.tick(60)
run = True
while run:
    screen.fill((255, 255, 255))

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

        if randb4 == 1:
            bot4x = bot4x + 5
        elif randb4 == 2:
            bot4x = bot4x - 5
        elif randb4 == 3:
            bot4y = bot4y + 5
        elif randb4 == 4:
            bot4y = bot4y - 5

        if bot4x >= 568:
            bot4x = 568
        elif bot4x <= 0:
            bot4x = 0
        elif bot4y >= 568:
            bot4y = 568
        elif bot4y <= 0:
            bot4y = 0
    bot4()
    pygame.display.update()

Solution

It is a matter of Indentation. You have to compute the movement in the application loop instead of the event loop:

pygame.init()
clock = pygame.time.Clock()

bot4x = random.randint(0, 600)
bot4y = random.randint(0, 600)

randb4 = round(random.randint(0, 4))

def bot4():
    screen.blit(pygame.image.load("DOT.png"), (bot4x, bot4y))

clock.tick(60)
run = True
while run:
    screen.fill((255, 255, 255))

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    # INDENTATION
    #<--|

    if randb4 == 1:
        bot4x = bot4x + 5
    elif randb4 == 2:
        bot4x = bot4x - 5
    elif randb4 == 3:
        bot4y = bot4y + 5
    elif randb4 == 4:
        bot4y = bot4y - 5

    if bot4x >= 568:
        bot4x = 568
    elif bot4x <= 0:
        bot4x = 0
    elif bot4y >= 568:
        bot4y = 568
    elif bot4y <= 0:
        bot4y = 0

    bot4()
    pygame.display.update()